RahuIII
After you Beat Grand Battle Mode, go back to the 'Outside world' Amusment park. Enter the Silver Battle Royal and do not skip the senario. Before the match starts walk straight down until you find a broken carriage. You can enter the carriage on the right side. Inside tap A like crazy till you pick up a data chip. And now you have big, bad Rahu3.

Fresh Stage
Go to VS mode highlight the basic arena or No Manís Land and press Z.

Ray Legend
Get a gold trophy in all cups in the Z headquarters then talk to Oboro.

Ray Warrior
Get a gold trophy in all the cups in the Amusement Park, then talk to the policeman at the front gate.

Parts Index
Beat a new journey in story mode.

Completion Bonuses
To unlock Arcade Mode, First Person View, Parts Index, and The Grand Battle in Single, and Versus Mode CPUs, you must complete 'A New Journey' mode in single player.

Alternate Arena Graphics
At the arena select screen in VS. mode, hold the Z button on Basic Arena or No Man's Land to play with alternate graphics for those stages.